The present invention relates to a switch device employing a bimetal plate which has a body and two legs extending from the body. A conduction member is connected between the two legs. The area of the bimetal plate is smaller than the conventional bimetal plate.
A conventional bimetal plate 6xe2x80x2 used in a switch device is shown in FIG. 5b and generally is an elongated metal plate involving two metal materials therein. Two ends of the bimetal plate 6xe2x80x2 are pressed to be a recess 61xe2x80x2 and a protrusion portion 62xe2x80x2 is punched in a mediated portion of the bimetal plate 6xe2x80x2. The protrusion portion 62xe2x80x2 makes the mediate portion be higher than the two ends and the two recesses 61xe2x80x2 provide a tension to let the bimetal plate 6xe2x80x2 have a tendency to jump upward when heated. The conventional bimetal plate 6xe2x80x2 has a certain width and size limitation so that the size of the switch receiving the bimetal plate 6xe2x80x2 cannot be reduced. Besides, the east of the bimetal plate 6xe2x80x2 is high so that the larger area the bimetal plate 6xe2x80x2 is, the higher the cost of the switch device is.
The present invention intends to provide an improved bimetal plate that has a body with two legs and has smaller area than the conventional bimetal plate.
The primary object of the present invention is to provide a switch device that employs a U-shaped bimetal plate which has a smaller area compared with the conventional bimetal plate. In accordance with one aspect of the present invention, there is provided a switch device that comprises a switch case having a passage for receiving a button therein. A non-conductive plate extends laterally from the button and is located in the switch case. A first terminal plate and a second terminal plate respectively extend from an underside of the case. A bimetal plate has a body and two legs extend from the body. The body is connected to the first terminal plate. A conductive member is connected between the two legs and contacts the second terminal plate. The L-shaped non-conductive plate is movably located between the conductive member and the second terminal plate when the two legs are deformed away from the second terminal plate as a result of current overriding.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.